How do I prepare for an AP audit?

PBC - "prepared by client" - is the auditor's request list of schedules and evidence you must produce. The AP staples: the AP aging at period end, reconciled to the GL; the full invoice population for the period (auditors increasingly run analytics on it); accrual schedules and supporting methodology; samples' support packages (invoice, PO, receipt evidence, approval record, payment evidence); vendor master change listings; user access listings for in-scope systems; and the subsequent disbursements population for the unrecorded-liabilities search. Treat the PBC list as a production schedule - assign owners and dates per item, and version-control what you deliver.

Per sampled invoice, the package shows the complete chain: the invoice itself, the PO and receiving evidence where applicable, the coding, the approval history (who, when, at what amount, under what authority - including any delegation), and the payment record. The quality bar is self-sufficiency: the auditor shouldn't need you in the room to follow it. In a system that keeps the trail on the invoice, this is an export per sample; in a fragmented process it's the single biggest time sink of fieldwork - which is worth remembering when invoices are flowing, not when the sample lands.

Let the system be the filing cabinet: every invoice carries its documents, approvals, and history as work happens, vendor records hold their compliance docs, and month-end reconciliations get saved with their support when performed. The year-round discipline isn't extra work - it's refusing to let evidence live in inboxes.

Typically: invoice agrees to support (vendor, amount, date); properly coded to account and period; matched to PO/receipt where applicable; approved by someone with appropriate authority per your DOA; approval preceded payment; payment agrees to the bank; and recorded in the right period. Design your evidence package so each attribute is answerable on its face.

Run the aging as of period end and reconcile it to the GL control account, documenting and resolving differences before delivery. For accruals, keep the methodology memo current and the support (unprocessed invoices, estimates basis) attached to the schedule. Stale reconciling items are the most common avoidable finding in this package.

Produce what exists (paper files, email archives, old system exports), be explicit about the cutover date and what evidence standards applied before it, and don't backfill - a reconstructed approval is worse than a disclosed gap. Auditors routinely handle system transitions; what they need is a clear boundary and honest completeness.

Highly variable by size and scope: AP-focused fieldwork commonly runs days to a few weeks, with control samples in the 25 - 60 range per key control and substantive samples driven by population and risk. Your evidence turnaround time is the lever you control - slow PBC responses stretch fieldwork more than sample counts do.

Route everything through one owner (usually the AP manager or controller) so answers are consistent and tracked; log every request and response. Escalate to the controller/CFO anything touching judgment (accrual methodology, exception explanations, potential findings) - staff shouldn't be improvising answers that become audit evidence.

Monthly, not annually: compare the subledger total to the AP control account, identify differences (timing, manual journal entries to the control account, unposted batches), and clear them. Manual JEs against the AP control account are the usual culprit - restrict them, and document any that remain.

Reconcile subledger to GL and clear old reconciling items; purge or investigate stale open invoices and credits; document your approval policy and confirm system routing matches it; run a self-test on a sample of your own invoices against the attribute list; tighten user access; and prepare the PBC staples in advance. The goal isn't perfection - it's no surprises you didn't already know about.

Stampli is built so audit season is retrieval, not reconstruction: every invoice carries its own complete history - documents, coding changes, approval chain with delegation, comments, and sync events - and invoice data can be exported on request. Audit-ready accountability is a platform capability, not an add-on: the evidence auditors ask for is the same record AP used to do the work, so sample requests that used to take days of assembly become selections and downloads.